Cellular wireless communication system, as shown in FIG. 1, mainly consists of a Core Network (CN), a Radio Access Network (RAN) and a terminal. The CN holds responsibility for non-access layer services (for example, update of terminal location) and serves as an anchor of user plane. The access network includes a base station or includes a base station and a base station controller, and the access network holds responsibility for access layer services (for example, management of radio resources). A physical or logical connection may exist between base stations according to actual conditions, such as the connection between the base station 1 and the base station 2 or base station 3 as shown in FIG. 1; moreover, each base station can connect with one or more core network nodes. The terminal, that is, User Equipment (UE), refers to various devices which can communicate with the cellular wireless communication network, for example, a mobile phone or notebook.
Hereinafter, an introduction is provided for following CN network elements:
Short Message Service Centre (SMS-SC), which generates the content of a short message and packages it as a short message packet according to a short message protocol;
Mobility Management Unit (Mobility Management Entity (MME) or Serving GPRS Support Node (SGSN) or Mobile Switching Centre (MSC)), which is the unit responsible for terminal access control, location information update and switch in a CN, and holds responsibility for non-access layer signalling control from the CN to a terminal and registration of the terminal in a network;
Packet Data Network Gateway (P-GW) or Gateway GPRS Support Node (GGSN), which is the network element responsible for IP address allocation, session management, PCRF selection, route selection and data forwarding, QoS control, charging, policy and charging enforcement in the CN;
Serving Gateway (S-GW), which is the network element responsible for session management, route selection and data forwarding, QoS control, charging and information storage in the CN; and
Machine Type Communication-Inter Working Function entity (MTC-IWF), which is a connection entity between a mobile communication network and an external public network and can implement functions such as protocol conversion, address query and information storage. The MTC-IWF is connected to an MTC server externally and is connected to the network elements in the mobile communication network internally, such as Home Subscriber Server (HSS) and/or Home Location Register (HLR), or MME and/or SGSN and/or MSC.
In some MTC applications, for example, if a monitoring management system needs to acquire monitoring data from a monitoring terminal, it is needed to trigger, through a server, the terminal to establish a connection with the server to report the desirable data. Then, the terminal needs to respond immediately and establishes a connection with the server, after receiving a trigger message from the server. At present, in order to meet the requirement of triggering a terminal by a server, existing solutions attempt to indicate a network to remove a trigger message when the trigger message expires by including the valid time of the trigger message in the trigger message.
However, in prior art there is no mechanism for a network to correctly parse and implement the valid time of a trigger message, this inevitably causes a wrong removal of the trigger message by the network, thus resulting in a failure of triggering a terminal or a waste of network storage resources.